Inkjet printing has become a popular way of recording images on various media surfaces, particularly paper, for a number of reasons, including, low printer noise, capability of high-speed recording, and multi-color recording. Additionally, these advantages of inkjet printing can be obtained at a relatively low price to consumers. Though there has been great improvement in inkjet printing, improvements are followed by increased demands from consumers for higher speeds, higher resolution, full color image formation, increased stability, etc.
In recent years, as digital cameras and other digital image collecting devices have advanced, image recording technology has attempted to keep pace by improving inkjet image recording on paper sheets and the like. The desired quality level of the inkjet recorded images (“hard copy”) is that of traditional silver halide photography. In other words, consumers would like inkjet recorded images that have the color reproduction, image density, gloss, etc. that is as close to those of silver halide photography as possible.
Ink-jet inks typically comprise an ink vehicle and a colorant, the latter of which may be a dye or a pigment. Dye-based ink-jet inks used in photographic image printing typically include water-soluble dyes.
For ink-jet inks, print media surfaces play a key role in the overall image quality, water resistance, and permanence of the ink-jet produced printed images. Inkjet recording materials designed for dye based inks can generally be separated into two broad groups: porous media and swellable media.
During printing on a porous media, ink is quickly adsorbed onto the surface which is porous in nature, and if an ionic binding species is present, the colorant can be attracted to the ionic species of opposite charge. Upon printing on swellable media, ink is absorbed as water contacts and swells a polymer matrix of the coating. The colorant, which is typically a dye, can be immobilized inside the continuous layer of the polymer with significantly limited exposure to the outside environment.